A brainteaser about the uncanny connections between a burglar and the baseball player he fanatically cheers, "Potechi" is as mathematical and diverting as a Rubik's cube.

A brainteaser about the uncanny connections between a burglar and the baseball player he fanatically cheers, “Potechi” is as mathematical and diverting as a Rubik’s cube. In his fourth film adapted from a Kotaro Isaka mystery novel, Yoshihiro Nakamura (“Golden Slumber,” “Fish Story”) lays out the writer’s intricate plot with clarity and delightfully offhand irony. Production may be pint-sized, but this seemingly trivial yarn, enriched by its setting in post-tsunami Sendai, actually ponders huge questions about fate and coincidence. Still, its 68-minute runtime makes it an awkward fit for theatrical release; even TV broadcast outside Japan might be a longshot.

Two men sit in a park, as if whiling away their time. Their conversation, however, reveals them to be house burglars, with the younger Tadashi (Gaku Hamada) enlisting maverick veteran Kurosawa (Nao Omori) to help him with a job. In the next scene, Tadashi and Wataba (Fumino Kimura), his g.f.-cum-partner-in-crime, have broken into the apartment of baseball player Ozaki (Ryohei Abe), who, despite having been a local hero in high school, is now just getting by as a member of the Sendai Kings.

Tadashi and Wataba overhear a voicemail that leads to a meeting with young hottie Miyu (Mayu Matsuoka), who tells them Ozaki once saved her from a stalker. Since Tadashi is Ozaki’s loyal fan and even shares his birthday, he and Wataba decide to scare off the stalker themselves. At a crucial juncture, Kurosawa intervenes, delivering a payoff at a climactic game that’s the dramatic equivalent of a home run.

As always with Isaka’s novels and Nakamura’s adaptations, the narrative is propelled by flashbacks that, despite their vague chronology, are inserted at just the right times, such as a suspenseful, enigmatic moment when Kurosawa invites Wataba to go up to his hotel room. So compact is the film’s structure that one cannot afford to overlook a single frame or line of dialogue; a case in point is a scene that not only explains the title (“potechi” means “potato chips”) but also underscores a key leitmotif. One of the pic’s many deceptively simple techniques is to have two characters sit side-by-side and chat (occasionally in the presence of a third person), an initially monotonous setup that gains visual relevance with each revelation, up to and including the climax.

Set in Sendai, which was devastated by the March 11 catastrophe, “Potechi” is the rare film to address the tragedy in a blackly humorous context. Yet the protags’ continuous attempts to understand the workings of the universe and the impact of chance on human lives (implied in Tadashi’s musings on relativity in the opening scene) take on deeper shades of meaning in light of such a natural disaster. The pic’s perfect denouement offers the uplifting idea that, for every incident governed by fate or coincidence, there’s a counter-incident achieved through human intelligence and resourcefulness.

Hamada, who’s appeared in three other pics helmed by Nakamura, initially seems to overdo the sports fan zeal, but the baby-faced thesp elicits total sympathy as the full implications of his devotion emerge. However, it’s Omori who steals every scene, limning the mysterious, self-contained Kurosawa with godlike detachment and composure. Charming supporting turns by Eri Ishida as Tadashi’s big-hearted mother and Nakamura as Tadashi’s genial crime boss add a warm human touch to the schematic proceedings.